Subtilisin
Serine Endopeptidases
Bacillus
Enzyme Stability
Amino Acid Sequence
Substrate Specificity
Molecular Sequence Data
Breaking the low barrier hydrogen bond in a serine protease. (1/1189)
The serine protease subtilisin BPN' is a useful catalyst for peptide synthesis when dissolved in high concentrations of a water-miscible organic co-solvent such as N,N-dimethylformamide (DMF). However, in 50% DMF, the k(cat) for amide hydrolysis is two orders of magnitude lower than in aqueous solution. Surprisingly, the k(cat) for ester hydrolysis is unchanged in 50% DMF. To explain this alteration in activity, the structure of subtilisin 8397+1 was determined in 20, 35, and 50% (v/v) DMF to 1.8 A resolution. In 50% DMF, the imidazole ring of His64, the central residue of the catalytic triad, has rotated approximately 180 degrees around the Cbeta-Cgamma bond. Two new water molecules in the active site stabilize the rotated conformation. This rotation places His64 in an unfavorable geometry to interact with the other members of the catalytic triad, Ser221 and Asp32. NMR experiments confirm that the characteristic resonance due to the low barrier hydrogen bond between the His64 and Asp32 is absent in 50% DMF. These experiments provide a clear structural basis for the change in activity of serine proteases in organic co-solvents. (+info)Thaumatin production in Aspergillus awamori by use of expression cassettes with strong fungal promoters and high gene dosage. (2/1189)
Four expression cassettes containing strong fungal promoters, a signal sequence for protein translocation, a KEX protease cleavage site, and a synthetic gene (tha) encoding the sweet protein thaumatin II were used to overexpress this protein in Aspergillus awamori lpr66, a PepA protease-deficient strain. The best expression results were obtained with the gdhA promoter of A. awamori or with the gpdA promoter of Aspergillus nidulans. There was good correlation of tha gene dosage, transcript levels, and thaumatin secretion. The thaumatin gene was expressed as a transcript of the expected size in each construction (1.9 or 1.4 kb), and the transcript levels and thaumatin production rate decayed at the end of the growth phase, except in the double transformant TB2b1-44-GD5, in which secretion of thaumatin continued until 96 h. The recombinant thaumatin secreted by a high-production transformant was purified to homogeneity, giving one major component and two minor components. In all cases, cleavage of the fused protein occurred at the KEX recognition sequence. This work provides new expression systems in A. awamori that result in very high levels of thaumatin production. (+info)Subtilisin-like proprotein convertases, PACE4 and PC8, as well as furin, are endogenous proalbumin convertases in HepG2 cells. (3/1189)
Serum albumin is synthesized as a larger precursor form, proalbumin, which undergoes proteolytic processing at a dibasic site by a hepatic proprotein convertase within the secretory pathway to generate the mature form. Although furin, a member of the subtilisin-like proprotein convertase (SPC) family, was thought to be the only candidate hepatic convertase for proalbumin, SPC family members other than furin were recently suggested to also be involved in proalbumin processing. This study was designed to identify the endogenous proprotein convertases involved in proalbumin processing. Since human hepatoma HepG2 cells are highly differentiated and produce major plasma proteins, this cell line was used as a model for hepatocytes. Northern blot analysis revealed that PACE4, furin and PC8 of the SPC family were expressed in HepG2 cells as well as in the liver. Ribonuclease protection assay showed that PACE4A-II mRNA is the major transcript in HepG2 cells among the PACE4 isoforms. The coexpression studies showed that furin, PACE4A-II and PC8 were all able to convert proalbumin to albumin correctly. To elucidate the roles of these endogenous SPC family members in proalbumin processing, the antisense RNA for PACE4, furin and PC8 was stably expressed in HepG2 cells, respectively. The expression of each antisense RNA resulted in approximately 30% inhibition of endogenous proalbumin processing. We therefore concluded that PACE4 and PC8, as well as furin, are involved in the processing of proalbumin in HepG2 cells, and that these SPC family members are functionally redundant in this processing. (+info)Thyroid hormone receptor-associated proteins and general positive cofactors mediate thyroid hormone receptor function in the absence of the TATA box-binding protein-associated factors of TFIID. (4/1189)
Coactivators previously implicated in ligand-dependent activation functions by thyroid hormone receptor (TR) include p300 and CREB-binding protein (CBP), the steroid receptor coactivator-1 (SRC-1)-related family of proteins, and the multicomponent TR-associated protein (TRAP) complex. Here we show that two positive cofactors (PC2 and PC4) derived from the upstream stimulatory activity (USA) cofactor fraction act synergistically to mediate thyroid hormone (T3)-dependent activation either by TR or by a TR-TRAP complex in an in vitro system reconstituted with purified factors and DNA templates. Significantly, the TRAP-mediated enhancement of activation by TR does not require the TATA box-binding protein-associated factors of TFIID. Furthermore, neither the pleiotropic coactivators CBP and p300 nor members of the SRC-1 family were detected in either the TR-TRAP complex or the other components of the in vitro assay system. These results show that activation by TR at the level of naked DNA templates is enhanced by cooperative functions of the TRAP coactivators and the general coactivators PC2 and PC4, and they further indicate a potential functional redundancy between TRAPs and TATA box-binding protein-associated factors in TFIID. In conjunction with earlier studies on other nuclear receptor-interacting cofactors, the present study also suggests a multistep pathway, involving distinct sets of cofactors, for activation of hormone responsive genes. (+info)Analysis of protein-protein interactions by mutagenesis: direct versus indirect effects. (5/1189)
Site-directed mutagenesis, including double-mutant cycles, is used routinely for studying protein-protein interactions. We now present a case analysis of chymotrypsin inhibitor 2 (CI2) and subtilisin BPN' using (i) a residue in CI2 that is known to interact directly with subtilisin (Tyr42) and (ii) two CI2 residues that do not have direct contacts with subtilisin (Arg46 and Arg48). We find that there are similar changes in binding energy on mutation of these two sets of residues. It can thus be difficult to interpret mutagenesis data in the absence of structural information. (+info)Directed evolution converts subtilisin E into a functional equivalent of thermitase. (6/1189)
We used directed evolution to convert Bacillus subtilis subtilisin E into an enzyme functionally equivalent to its thermophilic homolog thermitase from Thermoactinomyces vulgaris. Five generations of random mutagenesis, recombination and screening created subtilisin E 5-3H5, whose half-life at 83 degrees C (3.5 min) and temperature optimum for activity (Topt, 76 degrees C) are identical with those of thermitase. The Topt of the evolved enzyme is 17 degrees C higher and its half-life at 65 degrees C is >200 times that of wild-type subtilisin E. In addition, 5-3H5 is more active towards the hydrolysis of succinyl-Ala-Ala-Pro-Phe-p-nitroanilide than wild-type at all temperatures from 10 to 90 degrees C. Thermitase differs from subtilisin E at 157 amino acid positions. However, only eight amino acid substitutions were sufficient to convert subtilisin E into an enzyme equally thermostable. The eight substitutions, which include known stabilizing mutations (N218S, N76D) and also several not previously reported, are distributed over the surface of the enzyme. Only two (N218S, N181D) are found in thermitase. Directed evolution provides a powerful tool to unveil mechanisms of thermal adaptation and is an effective and efficient approach to increasing thermostability without compromising enzyme activity. (+info)Differential sorting of nerve growth factor and brain-derived neurotrophic factor in hippocampal neurons. (7/1189)
Nerve growth factor (NGF) is released through the constitutive secretory pathway from cells in peripheral tissues and nerves where it can act as a target-derived survival factor. In contrast, brain-derived neurotrophic factor (BDNF) appears to be processed in the regulated secretory pathway of brain neurons and secreted in an activity-dependent manner to play a role in synaptic plasticity. To determine whether sorting differences are intrinsic to the neurotrophins or reflect differences between cell types, we compared NGF and BDNF processing in cultured hippocampal neurons using a Vaccinia virus expression system. Three independent criteria (retention or release from cells after pulse-chase labeling, depolarization-dependent release, and immunocytochemical localization) suggest that the bulk of newly synthesized NGF is sorted into the constitutive pathway, whereas BDNF is primarily sorted into the regulated secretory pathway. Similar results occurred with AtT 20 cells, including those transfected with cDNAs encoding neurotrophin precursor-green fluorescent protein fusions. The NGF precursor, but not the BDNF precursor, is efficiently cleaved by the endoprotease furin in the trans-Golgi network (TGN). Blocking furin activity in AtT 20 cells with alpha1-PDX as well as increasing the expression of NGF precursor partially directed NGF into the regulated secretory pathway. Therefore, neurotrophins can be sorted into either the constitutive or regulated secretory pathways, and sorting may be regulated by the efficiency of furin cleavage in the TGN. This mechanism may explain how neuron-generated neurotrophins can act both as survival factors and as neuropeptides. (+info)Sorting of furin at the trans-Golgi network. Interaction of the cytoplasmic tail sorting signals with AP-1 Golgi-specific assembly proteins. (8/1189)
The eukaryotic subtilisin-like endoprotease furin is found predominantly in the trans-Golgi network (TGN) and cycles between this compartment, the cell surface, and the endosomes. There is experimental evidence for endocytosis from the plasma membrane and transport from endosomes to the TGN, but direct exit from the TGN to endosomes via clathrin-coated vesicles has only been discussed but not directly shown so far. Here we present data showing that expression of furin promotes the first step of clathrin-coat assembly at the TGN, the recruitment of the Golgi-specific assembly protein AP-1 on Golgi membranes. Further, we report that furin indeed is present in isolated clathrin-coated vesicles. Packaging into clathrin-coated vesicles requires signal components in the furin cytoplasmic domain which can be recognized by AP-1 assembly proteins. We found that besides depending on the phosphorylation state of a casein kinase II site, interaction of the furin tail with AP-1 and its mu1subunit is mediated by a tyrosine motif and to less extent by a leucine-isoleucine signal, whereas a monophenylalanine motif is only involved in binding to the intact AP-1 complex. This study implies that high affinity interaction of AP-1 or mu1 with the cytoplasmic tail of furin needs a complex interplay of signal components rather than one distinct signal. (+info)Subtilisins are a group of serine proteases that are produced by certain bacteria, including Bacillus subtilis. They are named after the bacterium and the Latin word "subtilis," which means delicate or finely made. Subtilisins are alkaline proteases, meaning they work best in slightly basic conditions.
Subtilisins have a broad specificity for cleaving peptide bonds and can hydrolyze a wide range of protein substrates. They are widely used in industry for various applications such as detergents, food processing, leather treatment, and biotechnology due to their ability to function at high temperatures and in the presence of denaturing agents.
In medicine, subtilisins have been studied for their potential use in therapeutic applications, including as anti-inflammatory agents and in wound healing. However, more research is needed to fully understand their mechanisms of action and potential benefits.
Subtilisin is not strictly a medical term, but rather a term used in biochemistry and microbiology. It refers to a group of proteolytic enzymes (proteases) that are produced by certain bacteria, particularly Bacillus subtilis. These enzymes have the ability to break down other proteins into smaller peptides or individual amino acids by cleaving specific peptide bonds.
In a medical context, subtilisin might be mentioned in relation to its use in various commercial products such as detergents and contact lens cleaning solutions, where it helps to break down protein-based stains or deposits. Additionally, subtilisins have been explored for their potential applications in therapeutics, including the treatment of certain diseases caused by protein misfolding or aggregation, like cystic fibrosis and Alzheimer's disease.
However, it is important to note that direct medical definitions of 'subtilisin' are limited, as it primarily functions within the realms of biochemistry and microbiology.
Serine endopeptidases are a type of enzymes that cleave peptide bonds within proteins (endopeptidases) and utilize serine as the nucleophilic amino acid in their active site for catalysis. These enzymes play crucial roles in various biological processes, including digestion, blood coagulation, and programmed cell death (apoptosis). Examples of serine endopeptidases include trypsin, chymotrypsin, thrombin, and elastase.
'Bacillus' is a genus of rod-shaped, gram-positive bacteria that are commonly found in soil, water, and the gastrointestinal tracts of animals. Many species of Bacillus are capable of forming endospores, which are highly resistant to heat, radiation, and chemicals, allowing them to survive for long periods in harsh environments. The most well-known species of Bacillus is B. anthracis, which causes anthrax in animals and humans. Other species of Bacillus have industrial or agricultural importance, such as B. subtilis, which is used in the production of enzymes and antibiotics.
Enzyme stability refers to the ability of an enzyme to maintain its structure and function under various environmental conditions, such as temperature, pH, and the presence of denaturants or inhibitors. A stable enzyme retains its activity and conformation over time and across a range of conditions, making it more suitable for industrial and therapeutic applications.
Enzymes can be stabilized through various methods, including chemical modification, immobilization, and protein engineering. Understanding the factors that affect enzyme stability is crucial for optimizing their use in biotechnology, medicine, and research.
An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.
Substrate specificity in the context of medical biochemistry and enzymology refers to the ability of an enzyme to selectively bind and catalyze a chemical reaction with a particular substrate (or a group of similar substrates) while discriminating against other molecules that are not substrates. This specificity arises from the three-dimensional structure of the enzyme, which has evolved to match the shape, charge distribution, and functional groups of its physiological substrate(s).
Substrate specificity is a fundamental property of enzymes that enables them to carry out highly selective chemical transformations in the complex cellular environment. The active site of an enzyme, where the catalysis takes place, has a unique conformation that complements the shape and charge distribution of its substrate(s). This ensures efficient recognition, binding, and conversion of the substrate into the desired product while minimizing unwanted side reactions with other molecules.
Substrate specificity can be categorized as:
1. Absolute specificity: An enzyme that can only act on a single substrate or a very narrow group of structurally related substrates, showing no activity towards any other molecule.
2. Group specificity: An enzyme that prefers to act on a particular functional group or class of compounds but can still accommodate minor structural variations within the substrate.
3. Broad or promiscuous specificity: An enzyme that can act on a wide range of structurally diverse substrates, albeit with varying catalytic efficiencies.
Understanding substrate specificity is crucial for elucidating enzymatic mechanisms, designing drugs that target specific enzymes or pathways, and developing biotechnological applications that rely on the controlled manipulation of enzyme activities.
Hydrolysis is a chemical process, not a medical one. However, it is relevant to medicine and biology.
Hydrolysis is the breakdown of a chemical compound due to its reaction with water, often resulting in the formation of two or more simpler compounds. In the context of physiology and medicine, hydrolysis is a crucial process in various biological reactions, such as the digestion of food molecules like proteins, carbohydrates, and fats. Enzymes called hydrolases catalyze these hydrolysis reactions to speed up the breakdown process in the body.
Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.
In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."
1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.
2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.
3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.
4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).
Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.
Protease1
- a proteolytic activity inhibited by blended serine/cysteine protease inhibitors and turned on by Ca2+, features usual from the subtilisins. (iwap2018.com)
Proteins1
- Subtilisins are proteins which are readily and ultimately biodegradable in the environment. (heraproject.com)
Enzymes2
- Subtilisins are proteolytic enzymes, mainly (>90 %) used in detergents and household cleaning products to remove proteinaceous deposits and stains. (heraproject.com)
- Exposure limits are available for some contaminants, e.g. wood dust, subtilisins (bacterial enzymes) and flour dust. (scienceopen.com)
Bacterial1
- Subtilisins are of bacterial origin, and are produced by a fermentation process. (heraproject.com)
Proteases1
- Subtilisins belong to subtilases, a group of serine proteases that - like all serine proteases - initiate the nucleophilic attack on the peptide (amide) bond through a serine residue at the active site. (wikipedia.org)
Source2
- Both halophilic bacteria Pontibacillus marinus DSM 16465T and Alkalibacillus haloalkaliphilus DSM 5271T and both halotolerant bacteria Metabacillus indicus DSM 16189 and Litchfieldia alkalitelluris DSM 16976T served as a source for the four new subtilisins SPPM, SPAH, SPMI and SPLA. (bvsalud.org)
- KEY POINTS: â ¢ Halophilic and halotolerant Bacillaceae are a valuable source of new subtilisins. (bvsalud.org)